Leptomyrmex nigriventris

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Leptomyrmex nigriventris
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Leptomyrmex
Species: L. nigriventris
Binomial name
Leptomyrmex nigriventris
(Guérin-Méneville, 1831)

Leptomyrmex nigriventris casent0012212 profile 1.jpg

Leptomyrmex nigriventris casent0012212 dorsal 1.jpg

Specimen labels

Evolutionary Relationships
Leptomyrmex
Neotropical

Leptomyrmex neotropicus (fossil only)



Leptomyrmex relictus



Australasian
Micro-Leptomyrmex

Leptomyrmex burwelli



Leptomyrmex dolichoscapus



Macro-Leptomyrmex


Leptomyrmex mjobergi




Leptomyrmex varians




Leptomyrmex unicolor





Leptomyrmex flavitarsus



Leptomyrmex puberulus





Leptomyrmex darlingtoni




Leptomyrmex fragilis



Leptomyrmex niger











Leptomyrmex erythrocephalus




Leptomyrmex wiburdi




Leptomyrmex cnemidatus




Leptomyrmex nigriventris



Leptomyrmex tibialis









Leptomyrmex geniculatus




Leptomyrmex nigriceps



Leptomyrmex pallens






Leptomyrmex rufithorax




Leptomyrmex rufipes




Leptomyrmex rothneyi



Leptomyrmex ruficeps










Based on Barden et al., 2017. Note only selected Leptomyrmex species are included.

L. nigriventris has been recorded in rainforest, wet sclerophyll and dry sclerophyl. Nests occur under rocks, at tree bases, and in soil.

Identification

This is one of the largest Leptomyrmex species, second in size only to its sister species, Leptomyrmex tibialis. Tibial coloration (pale in L. nigriventris; dark in L. tibialis) distinguishes these taxa. Leptomyrmex nigriventris and L. tibialis co-occur in the region of Dorrigo, New South Wales. Large body size (HW 1.49–1.76 mm; WL 4.32–4.98 mm), a broad head (CI 0.66–0.75), 10+ standing hairs on the posterior face of the hind tibia, and a consistent color pattern (orange head and body with a black gaster) will separate this species from all others. No type specimen of L. nigriventris was found; however, the details in the type description and illustration allow unambiguous identification of this species. (Lucky and Ward 2010)

Identification Keys including this Taxon

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

These conspicuous ants are most often encountered individually or as small groups of 2 or 3 foragers on the surface of the ground any time of the day or night. Because of their long legs and thin bodies, they superficially resemble spiders. This is especially true when they are disturbed, as they extend their legs, raise their gasters, and run quickly to escape danger. This has led to their being given the common name "spider ants."

Nests are found in soil or in dead wood, either standing or on the ground, and are often at the base of trees. Colony sizes average a few hundred workers and a single queen. In all but a handful of species, the queen is wingless and worker-like, differing from workers only in being slightly larger and with an enlarged mesosoma. In a few species the queens are fully winged, as they are in most other ants.

When a large source of food is found, workers of Leptomyrmex will return to their nest and recruit additional workers to help utilise the newly found resource. They also use workers as "living storage vessels". These special workers, called repletes, accept liquids from returning foragers who transfer their liquid foods to these selected workers. These special workers continue to accept liquids until their gasters become greatly enlarged and extended. When enlarged, repletes cannot escape the nest and remain inside suspended from the ceiling. They can retain these fluids for extended periods and dispense it on demand when food is in short supply.

Castes

Queens have yet to be collected.

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • nigriventris. Formica nigriventris Guérin-Méneville, 1831, pl. 8, fig. 4 (w.) AUSTRALIA. Wheeler, W.M. 1915d: 261 (l.); Wheeler, W.M. 1934c: 95 (m.). Combination in Leptomyrmex: Mayr, 1862: 696. Junior synonym of erythrocephalus: Mayr, 1876: 77. Revived from synonymy as subspecies of erythrocephalus: Emery, 1887a: 252. Revived status as species: Emery, 1895g: 351. See also: Lucky & Ward, 2010: 42.

Type Material

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Lucky and Ward (2010) – measurements (n = 10) HL 2.27–2.53, HW 1.49–1.76, MFC 0.34–0.47, IOD 0.88–1.06, SL 3.67–4.15, EL 0.42–0.52, WL 4.32–4.98, PW 1.34–1.53, DPW 0.55–0.66, HTL 4.52–5.20, HTWmin 0.17–0.21, HTWmax 0.29–0.36, CI 0.66–0.75, SI 2.32–2.46, OI 0.08–0.11, HTC 0.52–0.66.

Large species (HW 1.49–1.76 mm; WL 4.32–4.98 mm) with very broad head (CI 0.66–0.75). Excluding mandibles, head width nearly 3/4 of head length, broadest at eye level, narrowing anteriorly to concave genae. Posterior to eyes, sides of head broadly rounded and postocular margin broadly rounded. Masticatory margin of mandible with approximately 9 large teeth and 7 denticles interspersed. Anterior clypeal margin medially concave. Eyes positioned posterior to midline of head, small and hairless, not surpassing lateral margins of head. Antennal scapes not compressed, extending beyond posterior margin of head less than 2/3 of their length.

Pronotum rather short, less than 1.5 times as long as broad. Declivity of propodeum about half the length of the dorsal face, which is slightly concave in profile, and bears a longitudinal impression. Petiolar node high, summit convex and rounded. Posterior face of petiole flat to concave, longer than anterior face ventral surface of petiole, which is flat to feebly convex A distinct longitudinal impression lends a bilobed appearance to the petiole in anterior view. Gaster broad and elliptical. Femora and tibiae somewhat compressed (HTC 0.52–0.66).

Surface subopaque, finely and densely shagreened. Mandibles slightly shining, coarsely punctate along apical margin. Pubescence extremely short and fine, covering the body and appendages. Pilosity on mandibles and clypeus short and yellow. Hairs on venter of gaster and coxae longer and black. Posterior face of hind tibia with ten or more short, brown bristles. Body rufotestaceous throughout, except for black gaster. Head and scapes a deeper, purplish red than remainder of body.

Male

Lucky and Ward (2010) – measurements (n = 3) HL 1.91–2.10, HW 1.30–1.42, SL 0.79–0.86, EL 0.54–0.65, HTL 4.52–4.72, CI 0.67–0.69, SI 0.61–0.62, SI2 1.40–1.60.

Wheeler (1934) - Head twice as long as broad through the eyes and shaped much like that of erythrocephalus cnemidatus but the mandibles with the blunt tips and masticatory borders very minutely denticulate. Eyes small compared with those of cnemidatus, scarcely longer than the cheeks. Ocelli small, with impressed internal orbits. Antennae long; scapes fully four times as long as broad; first funicular joint longer than broad, second twice as long as broad; joints 3-6 much longer and each distinctly bent near its distal end. Thorax shaped as in cnemidatus. Petiole like that of the worker, with the node subrectangular in profile. Gaster short, elongate-elliptical. Genitalia smaller and more retracted; the stipites small, triangular and pointed; volsellae very slender, pickaxe-shaped, the anterior prong long and acutely pointed, the posterior curved and much shorter; sagittra uncinate. Legs very long; median tibiae bowed; hind femora somewhat angularly bent in the middle; hind tibiae slightly flexuous at their tips. Wings rather small and narrow, only 7 mm. long. Pterostigmal appendage small, pedunculate, sausage-shaped; cubital vein completely absent in both fore wings.

Finely shagreened and subopaque; gaster somewhat more shining.

Hairs and pubescence whitish, the former absent, except on the mandibles and external genital valves; pubescence very fine and appressed, rather uniform over the surfaces of the body and appendages.

Yellowish brown; mesonotum with an anteromedian and a pair of lateral darker brown spots; gaster black, base of its first segment yellow; distal two-thirds of middle and hind femora blackish. Wings distinctly and uniformly infuscated; their veins pale yellow, with brown outlines.

References

  • Emery, C. 1887b [1886]. Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia. [part]. Ann. Mus. Civ. Stor. Nat. 24[=(2)(4): 241-256 (page 252, Revived from synonymy as variety of erythrocephalus)
  • Emery, C. 1895h. Descriptions de quelques fourmis nouvelles d'Australie. Ann. Soc. Entomol. Belg. 39: 345-358 (page 351, Revived status as species)
  • Guérin-Méneville, F. E. 1831. Insectes, plate 8. In: Duperrey, L. I. (ed.) 1830-1831. Voyage autour du monde, exécuté par ordre du Roi, sur la corvette de sa Majesté, La Coquille, pendant les années 1822, 1823, 1824 et 1825. Zoologie. Atlas, Insectes. Paris: H. Bertrand, pls. 1-21, 14 bis. (page ?, pl. 8, fig. 3 worker described)
  • Lucky, A. 2011. Molecular phylogeny and biogeography of the spider ants, genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 59: 281-292. doi:10.1016/j.ympev.2011.03.004
  • Lucky, A. & Ward, P.S. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr. Zootaxa 2688: 1-67. PDF
  • Mayr, G. 1862. Myrmecologische Studien. Verh. K-K. Zool.-Bot. Ges. Wien 12: 649-776 (page 696, Combination in Leptomyrmex)
  • Mayr, G. 1876. Die australischen Formiciden. J. Mus. Godeffroy 12: 56-115 (page 77, Junior synonym of erythrocephalus)
  • Wheeler, W. M. 1915e. The Australian honey-ants of the genus Leptomyrmex Mayr. Proc. Am. Acad. Arts Sci. 51: 255-286 (page 261, larva described)
  • Wheeler, W. M. 1934c. A second revision of the ants of the genus Leptomyrmex Mayr. Bull. Mus. Comp. Zool. 77: 69-118 (page 95, male described)